The San Onofre Nuclear Generating Station in Southern California is designed to withstand a 7.0-magnitude earthquake and 25-foot-high tsunami waves. Photo courtesy US Nuclear Regulatory Commission.

Japanese officials announced this morning that radiation levels have fallen at the Fukushima Daiichi nuclear plant that was rocked by Friday’s 9.0-magnitude earthquake and tsunami. Earlier the government had warned that radiation leaks from the plant—which houses six nuclear reactors—had reached harmful levels.

The threat at Fukushima Daiichi has prompted countries across the world to reassess their existing nuclear plants, and plans for new ones. The crisis marks the first major nuclear threat since a nuclear power plant in Chernobyl, Ukraine, exploded in 1986—a tragic accident that took a toll not only on human health, but on the environment, too. “The radioactive shock when the Chernobyl reactor exploded in 1986 combined with chronic low-dose contamination has resulted in morphologic, physiologic, and genetic disorders in every animal species that has been studied—mammals, birds, amphibians, fish, and invertebrates,” a 2009 study in the Annals of the New York Academy of Sciences found.

In light of Japan’s emergency, some European countries announced delays or changes to their nuclear energy plans, Reuters reports. Germany, for instance, will stop reactors accounting for a quarter of its nuclear capacity as part of a nationwide safety review that will run through June, keeping its seven oldest reactors offline during the moratorium, Businessweek reports.

Yet Japan’s crisis hasn’t deterred plans to build nuclear power plants in Latin America or Southeast Asia. The Indian government plans to move forward with rapid construction of new nuclear facilities, though it may re-evaluate and strengthen safety standards, possibly delaying projects. Elsewhere in the region, countries with no nuclear plants are also furthering plans to build reactors, including Indonesia, Malaysia, Thailand, and Vietnam, Voice of America reports.

In the U.S., fears surrounding nuclear plants as a result of Chernobyl and the 1979 Three Mile Island accident have lessened, and there’s been a push in recent years to increase nuclear power capacity. There are currently 104 nuclear power reactors in the U.S., and operators are seeking permits to build at least 20 more. Just last week House Republicans introduced a bill to issue permits for 200 new commercial nuclear reactors—“enough to triple current megawatt capacity, by 2040.” Additionally, the legislation calls for possibly reviving Nevada’s Yucca Mountain as a nuclear waste storage site.

At this point, it’s unclear what will happen to the bill or to the proposed plants that have already cleared some government environmental hurdles, such as two reactors slated for construction at NRG Energy’s plant 90 miles southwest of Houston.

"The science says that we could see about five miles from the [San Onofre] plant an earthquake, perhaps equal to a magnitude 6.5, 6.6," said Gil Alexander of Southern California Edison. "So we designed the plant to exceed the maximum threat. It's designed to withstand a 7.0."

But the images of destruction from Japan suggest our best science may fall short when it comes to predicting the destructive power of nature. And experts say Japan's earthquake readiness has always been more rigorous, reports CBS News correspondent John Blackstone. "Nobody's ever prepared for this kind of earthquake, but compared to Japan, probably we're not nearly as prepared as Japan," Tom Heaton, an engineering seismologist at Cal Tech, told Blackstone.

On the bright side, as confidence in nuclear power wanes, we may see a shift toward renewable energy sources like solar and off-shore wind.

"Shares in renewable energy industries yesterday rose while most other energy stocks fell," Clare Brook, fund manager of leading green investment group, WHEB, in London, told the Guardian. "This tragedy comes on top of the oil price rise, the BP disaster in the Gulf of Mexico and unrest in the Middle East, all of which has made renewables more attractive. We would expect investment in renewables, especially solar, to increase. Nuclear has become politically unacceptable.”

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